I looked in the manual that came with the Blade Z Max, but didn't find my answer.
When you are playing back a video you made, as you have the phone horizontal, at the bottom of the screen, in the lower left, is a pair of arrows pointing inward. If you touch that pair of arrows, they toggle to pointing outward. What is this function? Is there a legend that I can access online that shows this, or a legend for this in the phone somewhere?